Values Of K1 Research Articles

Yielding and K 0 Value Variation of Cemented Sand along a K 0 Path

The yield stress and the coefficient of lateral earth pressure at rest, K0, of soil are important parameters for geotechnical design. However, the effect of cementation on the values of yield stress and K0 of artificially cemented sand along a K0 path has not been fully studied, despite the common use of cement mixing for soil improvement. A series of consolidation tests of K0 on artificially cemented sand has been conducted using a plane-strain apparatus. The test results show that the value of K0 of cemented sand is very much affected by the amount of cementation; the lowest value of K0 in a K0 test corresponds to the yield stress provided by cementation. It is established in this study that the yield stress of cemented sand marks the start of a large amount of bond destruction. The value of K0 reduces exponentially with the increase in cement content. One important practical implication is that the lateral earth pressure at rest can be reduced by introducing cementation to soil. This study also shows that Jaky’s equation is no longer applicable for estimating the value of K0 of cemented sand, although it may still provide a rough estimate for clean sand. The value of K0 of cemented sand can be estimated using a combination of Jaky’s equation for clean sand and Jaky’s equation for cement content.

Static and dynamic properties of two-sublattice spin-crossover systems

We investigate the static and dynamic properties of spin-crossover systems in the presence of an external magnetic field using two-sublattice Ising-like Hamiltonian. At low temperatures both sublattices are in the LS state, and in the HS state at high temperatures. The new feature of spin-crossover is depicted for our model when we take the non-equivalent sublattices JA≠JB, the two-step spin-crossover phase transition is obtained with the presence of the hysteresis loop. In order to study the properties of two-step spin-crossover, we use the lowest approximation of the cluster variation method for static properties. The dynamic properties of the system with bilinear interactions are studied by the path probability method. We present high-spin state fraction nHS vs temperature and magnetic field variations for constant values of the degeneracy ratio between high-spin and low-spin states. In the present model, we obtained the relaxation curves of the order parameters SA and SB using different temperature values. Finally, the flow diagram of the order parameters is depicted for different values of rate constant k1 and temperature, which displays the stable, metastable, and unstable properties. Static and dynamic self-consistent equations of the system were performed by using Newton-Raphson and Runge-Kutta methods.

Adsorption studies of KOH-modified hydrochar derived from sugarcane bagasse for dye removal: Kinetic, isotherm, and thermodynamic study

Toxicity of methylene blue (MB) in water bodies has a negative effect on environment and living organisms. The presence of MB in water could last longer in view of the non-biodegradable characteristic. In this study, hydrochar was used as adsorbent to remove MB from aqueous solution. Hydrochar derived from bagasse was successfully prepared by hydrothermal carbonization treatment at temperature of 270oC, and pressure of 10 Bar for 30 minutes. For enhancing the adsorption ability, hydrochar was activated by adding KOH that was able to increase the percent removal by ~11%. The hydrochar was characterized using FTIR before and after adsorption. The results showed that the dominant functional groups of hydrochar included O-H, C=O, -O- and aromatic compounds. Whereas, the functional group of azo groups such as N-H and N=N appeared after adsorption. The maximum adsorption capacity (Qmax) was 5.1204 mg/g, while the adsorption isotherm of MB onto hydrochar followed the Langmuir and Freundlich model. The adsorption mechanism belongs to chemical adsorption, and the rate of diffusion can be neglected because the adsorption kinetics fitted well with pseudo-second order and the value of k2 > kdif > k1. Thermodynamic studies indicated that the adsorption process is classified as endothermic and reversible at room temperature. The results showed that hydrochar could be the alternative adsorbent for removing MB in wastewater. In addition, sugarcane bagasse has a great potential as feedstock of hydrochar.

Measurement of the Lateral Earth Pressure Coefficient of Clayey Soils by Modified Oedometer Test

The coefficient of lateral earth pressure at rest (K0) explains the connection between the effective vertical and lateral stresses. Geotechnical engineers have studied K0 for many years for its being a key element in the designs and analysis of various geotechnical problems such as slope stability, piles, and earth retaining structures. Moreover, K0 has played a critical phase in any numerical study of the soil-water combined geotechnical boundary value issues requiring parametric stress-strain time formulations During the previous few decades. A modified apparatus consisting of a standard Oedometer equipped with Force Sensitive Resistance (FSR) is used to investigate the value of lateral pressure () due to the vertical stress. The Oedometer test is carried out on three samples with different organic contents, with the K0 values obtained from each sample; empirical equations were also used to estimate K0 values for comparison purposes. From the analysis of the results, it can be stated that the K0 value is inversely proportional to the organic matter percent in the soil. It varies from 0.6125 in soil with 25.1% organic percent to 0.76 at a percent of 9.8%. The Force Sensitive Resistance (FSR) technique's performance is practical enough for estimating lateral earth pressure at rest (K0) of normally consolidated organic soil with many advantages; it is far less time-consuming and has a low operating cost than the traditional K0 estimate methods. Furthermore, K0 decreases with the increase of organic content.

Evaluation of the repeatability of optical coherence tomography in patients with age-related cataract associated with dry eye.

To assess the repeatability of a new optical biometer (OA-2000, Tomey, Japan) based on swept-source optical coherence tomography (SS-OCT) and Placido-disk topography in dry eyes with cataracts. A cross-sectional study was performed. Two hundred sixteen eyes of 216 cataract patients were enrolled in our hospital from March 2020 to December 2020. According to the subjective symptoms and objective examination of dry eye, the patients were assigned to dry eye group and non-dry eye group. Axial length (AL), keratometry readings (K), lens thickness (LT), anterior chamber depth (ACD), central corneal thickness (CCT) and white-to-white (WTW) distance were measured by one skilled operator. The repeatability of each parameter based on within-subject standard deviation (Sw), repeatability limit of standard deviation (2.77Sw), coefficient of variation (CoV) and intra-class correlation coefficient (ICC) was evaluated. There was no significant difference in age and gender between the two groups. NiaBUT and NifBUT in the dry eye group were significantly lower than those in the non-dry eye group (p < 0.05). The ICC mean values of AL, K1, K2, Km, ACD, LT and CCT were all greater than 0.960, except WTW. In the dry eye group, except CCT and WTW, the Sw scores for other biometric parameters were lower than 0.201, 2.77Sw scores were lower than 0.557, CoV(%) was less than 1%, and ICC mean values were greater than 0.964. Among them, the Sw scores for AL, LT and ACD were lower than 0.035, the 2.77Sw scores were lower than 0.097, and the ICC mean values are greater than 0.990. The ocular biological parameters measured by SS-OCT have good repeatability for age-related cataract patients with dry eyes, in which the AL, LT and ACD are the highest repeatable. However, more attention should be paid for WTW in clinical application since repeatability influence.

Monte Carlo Simulation and Reconstruction: Assessment of Myocardial Perfusion Imaging of Tracer Dynamics With Cardiac Motion Due to Deformation and Respiration Using Gamma Camera With Continuous Acquisition.

PurposeMyocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT) is routinely used for stress testing in nuclear medicine. Recently, our group extended its potential going from 3D visual qualitative image analysis to 4D spatiotemporal reconstruction of dynamically acquired data to capture the time variation of the radiotracer concentration and the estimated myocardial blood flow (MBF) and coronary flow reserve (CFR). However, the quality of reconstructed image is compromised due to cardiac deformation and respiration. The work presented here develops an algorithm that reconstructs the dynamic sequence of separate respiratory and cardiac phases and evaluates the algorithm with data simulated with a Monte Carlo simulation for the continuous image acquisition and processing with a slowly rotating SPECT camera.MethodsA clinically realistic Monte Carlo (MC) simulation is developed using the 4D Extended Cardiac Torso (XCAT) digital phantom with respiratory and cardiac motion to model continuous data acquisition of dynamic cardiac SPECT with slowly rotating gamma cameras by incorporating deformation and displacement of the myocardium due to cardiac and respiratory motion. We extended our previously developed 4D maximum-likelihood expectation-maximization (MLEM) reconstruction algorithm for a data set binned from a continuous list mode (LM) simulation with cardiac and respiratory information. Our spatiotemporal image reconstruction uses splines to explicitly model the temporal change of the tracer for each cardiac and respiratory gate that delineates the myocardial spatial position as the tracer washes in and out. Unlike in a fully list-mode data acquisition and reconstruction the accumulated photons are binned over a specific but very short time interval corresponding to each cardiac and respiratory gate. Reconstruction results are presented showing the dynamics of the tracer in the myocardium as it continuously deforms. These results are then compared with the conventional 4D spatiotemporal reconstruction method that models only the temporal changes of the tracer activity. Mean Stabilized Activity (MSA), signal to noise ratio (SNR) and Bias for the myocardium activities for three different target-to-background ratios (TBRs) are evaluated. Dynamic quantitative indices such as wash-in (K1) and wash-out (k2) rates at each gate were also estimated.ResultsThe MSA and SNR are higher with higher TBRs while biases were improved with higher TBRs to less than 10%. The correlation between exhalation-inhalation sequence with the ground truth during respiratory cycle was excellent. Our reconstruction method showed better resolved myocardial walls during diastole to systole as compared to the ungated 4D image. Estimated values of K1 and k2 were also consistent with the ground truth.ConclusionThe continuous image acquisition for dynamic scan using conventional two-head gamma cameras can provide valuable information for MPI. Our study demonstrated the viability of using a continuous image acquisition method on a widely used clinical two-head SPECT system. Our reconstruction method showed better resolved myocardial walls during diastole to systole as compared to the ungated 4D image. Precise implementation of reconstruction algorithms, better segmentation techniques by generating images of different tissue types and background activity would improve the feasibility of the method in real clinical environment.

Kinetics and Adsorption Equilibrium Study of Free Fatty Acid (FFA) from Crude Palm Oil (CPO) on Anionic Resin

Crude Palm Oil (CPO) is obtained from palm fruit extraction. Free Fatty Acid (FFA) level is one of the most important parameters to determine the CPO quality. The standard FFA level in the industry is less than 5%. In the palm oil processing industry, FFA levels in CPO have been minimized through vacuum distillation processes. However, due to the emulsified water in oil and long departure waiting time in port, FFA levels in CPO raise to above 5% resulting in lower quality and selling price. This study has developed a novel approach to mitigate this problem by using anionic resin as an adsorbent to decrease the FFA level. We investigated the kinetics and equilibrium behavior of FFA adsorption in CPO on the anionic resin. The adsorption was conducted in several resin dose (17.5%; 25%; 33.33%; 43%). The kinetic study shows that the FFA adsorption kinetics on anionic resin follows the Pseudo-second-order rate model with the value of k2 vary between 2.1034×10-4 – 1.7375×10-3 and the qe value is in the range of 103.627 - 163.880 (mg/g). The equilibrium study shows that the Freundlich isotherm model is the fittest. The Kf values are obtained between 4.16-15.02, and the n values are in the range of 1.62-2.05. The thermodynamic observation was also involved in this study. The value of and are 28.59 kJ/mol and 91.25 J/mol/K respectively. The results show that the reaction is endothermic, spontaneous, and feasible.

Improvement of the grapevine gene pool on the basis of agrobiological and physio-biochemical assessment of new genotypes under the unstable moderate continental climate conditions of Southern Russia

Background. Development of table grape cultivars is currently aimed not only at higher vineyard productivity and grape quality but also at enhancing the adaptive potential of plants under the dynamic change in the climate conditions of Southern Russia. Increasing the share of modern Russian cultivars of table grapes will update and improve the assortment. The aim of this study was to evaluate new Russian hybrid grapevine forms according to their agrobiological, physiological and biochemical characteristics in the central agroecological zone of Krasnodar Territory.Materials and methods. Agrobiological characters were assessed using modern methods. Among physio-biochemical characters, the content of photosynthetic pigments was measured as well as the level of stress parameters under drought, such as the total water content in leaves and the content of malondialdehyde. Artificial drought was simulated to identify the most stress-resistant hybrid forms.Results. The highest values of fruitfulness coefficients k1 and k2 in the period of research were recorded for the Akello and Agat Dubovsky hybrid forms. Timoti and Agat Dubovsky had the maximum average yield for two years among the hybrid forms. The Gamlet, Kishmish Dubovsky, Agat Dubovsky and Timoti genotypes significantly exceeded the reference cultivar in the bunch weight. The Akello and Agat Dubovsky hybrids were identified for their physio-biochemical parameters: the highest content of chlorophyll in their leaves, high adaptive potential expressed in a low development level of secondary oxidative processes under stress, and the highest content of carotenoids.Conclusion. The obtained results evidenced that the Agat Dubovsky hybrid form could be identified as the most promising among the studied genotypes for cultivation in Southern Russia.

Two Ligands of Interest in Recovering Uranium from the Oceans: The Correct Formation Constants of the Uranyl(VI) Cation with 2,2'-Bipyridyl-6,6'-dicarboxylic Acid and 1,10-Phenanthroline-2,9-dicarboxylic Acid.

The ligands BDA (2,2'-bipyridyl-6,6'-dicarboxylic acid) and PDA (1,10-phenanthroline-2,9-dicarboxylic acid) are of interest as functional group types for ion-exchange materials for extracting uranium from the oceans, reported in a previous paper for PDA Lashley, M. A. ( Inorg. Chem. 2016 55 10818 10829). Yang, Y. ( Inorg. Chem. 2019, 58, 6064 6074) have published what they claim to be a more accurate result for the formation of the UO22+/PDA complex of log K1 = 22.84 compared with our reported value of log K1 = 16.5, as well as log K1 = 21.52 for the BDA complex. The determination of log K1 for the PDA and BDA complexes with the UO22+ cation was carried out by Yang et al. using a competition reaction between DTPA (diethylenetriamine pentaacetic acid) and BDA or PDA, monitoring the absorbance due to the BDA and PDA ligands. This competition method using absorbance versus pH titrations was developed for determining the formation constants of the complexes of several polypyridyl ligands plus PDA complexes of metal ions, which were too stable for log K determination by competition with protons. A key feature of such titrations is that in the competition reaction, the displacement of the pyridyl donor ligand (e.g., PDA) by the competing ligand (e.g., DTPA), the absorbance spectrum of the displaced pyridyl donor ligand should be observed. Competing ligands used to date have been EDTA (ethylenediamine tetraacetic acid), DTPA, or the hydroxide ion. In the study of Yang et al., no such displaced PDA or BDA was apparent in the absorbance spectra in their titrations so that their reported log K1 values have no validity. Their log K1 values are so much higher than log K1 for the uranyl DTPA complex (∼13.6) that DTPA could not possibly displace BDA or PDA from the uranyl cation, and a competition reaction could not possibly occur. We report the correct value of log K1 = 15.4 (ionic strength = zero) for the uranyl BDA complex, to illustrate the correct determination of such a constant by a competition reaction between BDA and hydroxide, showing how the characteristic absorbance spectrum for a BDA complex, here the UO22+ complex, disappears, and the distinctive absorbance spectrum of the free nonprotonated BDA ligand appears as the pH is increased, and BDA is displaced by the hydroxide ion.

Comparison of keratometry versions in patients with corneal astigmatism

Purpose: to compare the corneal power at main meridians, the magnitude and the axis of corneal astigmatism and the reproducibility of measurements taken three times with different types of biometers.Material and methods. 22 subjects (24 eyes) with regular corneal astigmatism 1.89–8.02 D were given three biometry tests using IOL Master 500, Lenstar LS 900, IOL Master 700, Pentacam and Galilei G6.Results. The data were divided into groups depending on the principle of mathematical modeling of the corneal surface: group I involved the material processed by IOL Master 500, Lenstar LS 900, IOL Master 700; group II contained maps of the anterior corneal surface; and group III, those of the posterior surface. In group I, Lenstar showed the highest values of keratometry. In group II, the values of K1 , Kave in the 6 mm area were lower than in the pupil diameter area and than any values of K in the 4 mm area; the lowest values of K in this area were obtained on the Pentacam SimK. In group III, in the pupil diameter area (4.0–4.5 mm), all K values obtained with diverse equipment were different whilst in the 6 mm area the values differed only in the flat meridian. Astigmatism within groups I, III showed no difference while in group II the SimK data were different. The astigmatism axes obtained on IOLMaster 500 differed from the respective data provided by other devices. The devices of group I, 6 mm area, were the most stable.Conclusions. The highest values of keratometry are obtained when only the anterior surface of the cornea is taken into account, the lowest values are characteristic of the posterior surface. The stability of the parameter registered grew with the increase of the measured zone diameters. The biometers of group 1 showed the highest values of astigmatism with the maximum repeatability of the measurements

Crosslinking vs. Observation in Fellow Eyes of Keratoconus Patients.

Purpose To evaluate whether unilateral crosslinking (CXL) and conservative follow-up of the fellow eye is an acceptable management strategy in patients with keratoconus (KC). Methods Seventy-nine fellow eyes of KC subjects that initially underwent unilateral CXL were included. Thirty fellow eyes ultimately received CXL (group 1) whereas 49 fellow eyes were followed (group 2). Best spectacle corrected visual acuity (BSCVA) and corneal tomographic parameters were collected in all eyes preoperatively and at the last follow-up. Results Subjects who received CXL in the fellow eye (group 1) were younger than subjects who did not (group 2, p=0.026). Group 1 eyes had higher baseline K1 (p=0.026), K2 (p=0.006), Km (p=0.01), and Kmax (p=0.002) compared to group 2 eyes. Amongst the 49 naïve fellow eyes (group 2), 19 eyes showed evidence of progression. Progressing naïve eyes had higher baseline K1, K2, Km, and Kmax (p < 0.01); progressors also had thinner pachymetry at the pupil, apex, and thinnest point (p < 0.01). Baseline values of K1 ≥ 43.5 Diopter (D), K2 > 45.1D, Km > 44.3D, Kmax > 47.9D, astigmatism > 1.4D, pachymetry at the pupil <475 μm, and thinnest pachymetry <478 μm were tentative predictors of progression in the naïve fellow eye. Conclusions Unilateral CXL with vigilant follow up of the fellow eye may be an acceptable management strategy in a subset of KC eyes.

Application of heat carrier particles in a fluidized bed dryer: Dimensionless modeling and GHG emissions

AbstractDrying of agricultural products inherently is an energy intensive process. In the majority of drying processes, the energy for the air heating process is delivered by the steam, gas‐turbine, and combined‐cycle type power plants that run on the fossil fuels which in turn are responsible for global warming due to the greenhouse phenomena. The industry therefore is interested in the development of any energy saving measure in the drying process. This in turn reduces greenhouse gas (GHG) emissions. Optimization of the drying process for energy reduction by the mathematical modeling may provide means to accomplish this goal. In the present study, the drying of canola seeds in a fluidized bed dryer containing heat carrier particles was investigated. Drying kinetics was modeled using dimensionless groups and the GHG emissions in each process were determined and analyzed. Three temperature levels and four ratios of Heat Carrier Particle (HCP) to seeds were applied. The lowest specific energy consumption (least GHG emissions) was achieved when the air temperature was set at 60°C and the drying chamber was filled with a mass ratio of 0.5 of HCP to seeds. Values of R2, RMSE, and k2 obtained for the predicted and experimental data were 0.90, 0.017, and 0.00092 respectively.Practical applicationsIn the current investigation, specific energy consumption and GHG emissions in different drying conditions of canola seeds in a fluidized bed dryer containing heat carrier particles were calculated and compared. A dimensionless approach was used to establish a new model for drying of canola seeds in the fluidized bed dryer. Subsequently, a dimensionless equation describing the drying behavior of seeds was derived. This method while being a simple model, gives high precision data for all effective parameters in the drying process. Therefore, the establishment of a dimensionless model for the drying kinetics and investigation of GHG emissions in the present study can be useful for the development of Eco‐friendly drying methods for future usages in food process engineering.

Theoretical Study on Design of Composite Lining Structure with Rigid–Flexible Combination for Trenchless Pipeline Rehabilitation

Trenchless rehabilitation lining can be divided into flexible solid wall lining structures, rigid lining structures and rigid–flexible composite lining structures. This paper reviews the research status of the design theory of trenchless rehabilitation lining pipes, analyzes the theory of rigid–flexible composite lining structures, and points out that the value of the factor determined from non-grouting angle K1 is not clear in the design formula of the rigid–flexible composite lining structure mentioned in the ASTM ‘Standard Practice for Installation of Machine Spiral Wound Poly (Vinyl Chloride) (PVC) Liner Pipe for Rehabilitation of Existing Sewers and Conduits (ASTM F 1741)’. The value of K1 was obtained by the numerical analysis method with MATLAB software. Through the analysis of the variation trend of the K1 value, it is concluded that the design formula in the ASTM standard is only applicable to the case of incomplete grouting filling between the original pipe and the lining pipe, and is not applicable to the composite lining pipe with complete grouting filling. Finally, the explicit formula of the non-grouting angle is obtained by fitting, which is more convenient to use.

Kinetics of CO2 absorption into ethanolamine + water + ethanol system—mechanism, role of water, and kinetic model

The kinetics of CO2 absorption in ethanolamine (MEA) + H2O + ethanol systems was investigated using stopped-flow apparatus. The first-order reaction rate constant (k0) values were tested with varying H2O and MEA concentrations. Transiting from the aqueous to non-aqueous solvents, the k0 decreases and the reaction order for MEA shifts from 1.05 to 1.88. The zwitterion mechanism with the rate-limiting step of deprotonation was used to explore the role of water and its effect. Results showed that water could impact reactions through direct involvement and changing solvation environment. An improved kinetic model based on the zwitterion mechanism was obtained to indicate the quantitative influence of H2O concentration on the reaction kinetics of MEA + H2O + ethanol systems. The predicted values from the model well agreed to the experimental data with the average absolute relative difference of 6.73%. This study highlights the important effects of water on the reaction kinetics of CO2 absorption into water-lean amine solutions.

The effect of safety knowledge and workplace safety climate on safety performance with safety behavior as a mediator

This research examines the effect of safety knowledge and Workplace Safety Climate on safety performance mediated by worker safety behavior in the defense product manufacturing industry in Indonesia using PT Pindad as a research site. Occupational health and safety (K3) are one of the most important aspects of a company's production operations. No matter how good the quality or productivity of a company, it will be meaningless if there are problems regarding the value of K3 in its operations so that the K3 aspect cannot be ruled out. Safety knowledge of workers and creating a safety climate are able to achieve good safety performance. This study also measures the mediating effect of safety behavior in the causal relationship between safety knowledge and safety climate on safety performance. Questionnaires were distributed to 160 permanent employees. Then, Partial Least Squares are used to test the proposed hypothesis. The results showed that the safety knowledge variable was significantly related to the safety performance variable, with a count of 2.097, and the safety climate variable was significantly related to the safety performance variable, with an account of 2.243. The safety behavior variable mediates the effect of the safety knowledge variable on the safety performance variable, with a count of 2,607, and the safety behavior variable mediates the effect of the safety climate variable on the safety performance variable, with an account value of 2.094.

Comparative kinetic analysis of redox flow battery electrolytes: From micro-fibers to macro-felts

In the context of new aqueous organic electrolytes development for redox flow batteries, two different approaches of charge transfer kinetic constant determination on carbon-based felts are compared. The first one consists in direct electrochemical measurement on centimetric pieces of felts, referred to as macro-felts, and the second is based on electrochemical measurement on carbon fibers extracted from felts and conditioned as microelectrodes, referred to as micro-fibers. Quantitative cyclic voltammetry (CV) involving experimental data fitting or simulation and electrochemical impedance spectroscopy (EIS) are carried out on the two supports, with two typical aqueous organic electrolytes, and determined values for charge transfer kinetic constants are compared. k0 values analyzed from micro-fibers are systematically lower than that analyzed from macro-felts where the differences may reach ca. two orders of magnitude in some cases. CV and EIS analysis on micro-fibers show very good consistency. With the simplicity of physical analysis, micro-fibers are considered as a reliable and powerful tool for kinetic determination, especially when confronted to fast kinetics.

Impurity-impurity interaction during the growth of UMG-Si-based mc-Si

This article investigates the relationship between the chemical composition and electrophysical properties of p- and n-type multicrystalline silicon ingots based on metallurgical silicon with a purity of 99.99 at.%. In particular, the role of impurity-impurity interactions in the production of multisilicon by the Bridgman vertical method is evaluated in order to identify approaches to controlling this process effectively. The phase equilibrium calculations in the “silicon–all impurities” and “silicon-impurity-oxygen” systems were carried out based on the Gibbs energy minimization in the Selector software package. The study investigates the rank correlations of the concentrations of various impurities with each other, as well as with the specified electrical resistivity (SER) and the lifetime of nonequilibrium charge carriers (NCC) in the direction of crystal growth. Pair correlations of the element distribution profiles were considered based on the role of the main factor represented by the ratio of individual impurity solubilities in solid or liquid silicon (k0), as well as from the standpoint of direct interaction between two elements. It was found that the k0 value for two individual impurities in silicon does not automatically lead to the pair correlation of their distribution profiles in the ingot. A significant effect on the distribution profiles of impurities in multisilicon with k0→0 has the factor of binding some part of the impurity into such a form that this impurity can be incorporated easily into a growing crystal. Binding may be induced by the interaction of the impurity in the melt with the oxygen background, its segregation at the grain boundaries, and its capture by the crystallization front in the composition of the liquid inclusion. Significant correlations of impurity distribution profiles in the ingot were demonstrated by the pairs whose elements interact without the formation of chemical compounds in the 25–1413 °C temperature range. The conducted phase equilibrium calculations for the “silicon–all impurities” system revealed the possibility of forming the VB2, TiB2, ZrB2, and MgTiO4 solid phases in the melt.

Characterizing undrained shear behavior of loess subjected to K0 loading condition

Undrained shear behavior of loess after the K0 consolidation was investigated through laboratory experiments. Both the monotonic and cyclic triaxial tests were performed on the intact loess samples retrieved from a construction site in Yan'an city, China. It was found that the coefficient of lateral earth pressure at rest (K0) of the intact loess is stress-dependent, and it varies between 0.46 and 0.85. Under the monotonic loading condition, the peak q in the undrained shear test is higher for the samples under the K0 consolidation than those under the isotropic consolidation. Besides, the cyclic loading tests were conducted on the loess samples subjected to different magnitudes of the initial deviatoric stress, including the K0 stress state. The test results revealed that different initial stress conditions cause distinctly different failure patterns. It includes the cyclic mobility with progressive development of the axial strain, and limited deformation followed by an abrupt gain of the axial strain with no precursor. In accordance to the build-up of the excess pore water pressure during the tests, each failure pattern of loess was interpreted in the q-p' diagram alongside the undrained instability state (UIS) line. The outcomes of this paper suggest a pressing need to thoroughly consider the K0 values of the intact loess with variations of the initial stress state.

Non-Gaussian noise and autapse-induced inverse stochastic resonance in bistable Izhikevich neural system under electromagnetic induction

Inverse stochastic resonance refers to the phenomenon that the average firing rate of a neuron is inhibited by noise, of which mechanism is widely used in a variety of biological cells and economic phenomena. In this paper, a bistable Izhikevich neural model and triple-neuron feed-forward loop Izhikevich neural network motifs under the effects of electromagnetic induction are constructed to investigate the phenomenon of inverse stochastic resonance induced by Non-Gaussian colored noise and electrical autapse. It is found that there exists a minimum value of the average firing rate curve caused by intensity of non-Gaussian colored noise, which is the phenomenon of inverse stochastic resonance. Obtained results also show that the inverse stochastic resonance induced by electrical autapse shows a decaying oscillation process with respect to synaptic delay time, and further research indicates that average firing rate has several minimums as a function of time delay of electrical autapse, which is called multiple inverse stochastic resonance. Furthermore, the inverse stochastic resonance in triple-neuron feed-forward loop Izhikevich neural network motifs are also examined, and it is confirmed that the responses of single Izhikevich neuron and neural network motifs to different parameters show consistency under same conditions, but also show some differences. Finally, the effects of electromagnetic induction on inverse stochastic resonance are checked both in single Izhikevich neural model and feed-forward loop network motifs. Electromagnetic induction feedback gain coefficient k1 should not be too large under certain conditions, otherwise it may cause FFL network motifs to loss the function of suppressing the discharge activity. No matter how the values of electromagnetic induction parameter k2 and magnetic flux leakage coefficient k3 change, they basically cannot affect the ISR in the feed-forward loop neural network motifs The conclusions of this paper may help researchers understanding how using unique mechanism of inverse stochastic resonance to find advantages and avoid disadvantages in biomedical field and many interdisciplinary research.

COMPOSITION OF LIGHT HYDROCARBONS IN JURASSIC TIGHT OILS IN THE CENTRAL SICHUAN BASIN, CHINA: ORIGIN AND SOURCE ROCK CORRELATION

Crude oil reserves in tight Middle and Lower Jurassic reservoirs are of increasing exploration interest in the central Sichuan Basin, SW China. However, the origin of these “tight oils” is poorly understood. In this study, sixteen samples of light oils/condensates from tight Middle and Lower Jurassic reservoir rocks were analysed using gas chromatography (GC) and isotope ratio mass spectrometry to investigate the oils’ origin and to classify them into genetic families. The tight oils can be divided into two families. Family I oils occur in the Gongshanmiao oilfield where reservoir units comprise the Da'anzhai Member of the Lower Jurassic Ziliujing Formation, the Lower Jurassic Lianggaoshan Formation, and the First Member of the Middle Jurassic Shaximiao Formation. Family I oils are characterized by relatively low values of the methylcyclohexane (MCH) and cyclohexane (CH) indexes, low values of Mango's parameter K2 for light hydrocarbon composition, and relatively negative δ13C values ranging from ‐30.8‰ to ‐28.9‰. Family I oils are inferred to be self‐sourced by lacustrine shales in the Da'anzhai Member and the Lianggaoshan Formation in the study area, both of which are rich in sapropelic organic matter. These source rocks also charged reservoirs in the First Member of the Shaximiao Formation. By contrast, the newly discovered Family II oils, which occur at the Jinhua oilfield and the as‐yet undeveloped Qiulin and Bajiaochang structures, are reservoired in the Second Member of Shaximiao Formation. Family II oils have higher values of the MCH index, CH index and Mango's K2 parameter, and δ13C values varying from ‐27.5‰ to ‐25.4‰. These oils have similar light hydrocarbon compositions and δ13C values to oils derived from source rocks in the Upper Triassic Xujiahe Formation which contain dominantly humic organic matter. Family II oils are therefore inferred to be derived from the coaly mudstones in the Xujiahe Formation.The different compositions of the tight oils in the First and Second Members of the Shaximiao Formation appear to be controlled by the distribution and thickness of source rocks in the study area. Thus, the Gongshanmiao oilfield where Family I oils occur in the First Member is close to the depocentre of source rocks in the Da'anzhai Member and Lianggaoshan Formation. These source rocks are inferred to have charged the First Member reservoirs which may also be present in nearby oil‐ and gas‐bearing structures such as Nanchong and Yingshan. By contrast, Family II oils occur in tight reservoirs in the Second Member in areas with thick successions of Upper Triassic Xujiahe Formation mudstone source rocks, such as the Jinhua oilfield. In areas where both source rocks are present such as the Zhongtaishan and Lianchi oilfields, Shaximiao Formation reservoirs appear to contain both Family I and Family II oils.